The new service points users of Internet-enabled mobile devices to a special index of Web pages that have been optimized by their publishers for the small screen. The XHTML-based service takes advantage of the alignments of text, graphics and tables that mobile-aware publishers have created to make them easier to navigate on a mobile phone.

"Given that a lot of browsing does tend to happen outside the desktop, XHTML is an important new technology," said Deep Nishar, director of wireless product management for Google.

Google does a special Web crawl to create a separate index of XHTML pages, Nishar said; he wouldn't disclose how many pages were in the Mobile Web index, but said, "Many sites are using formats that are more conducive to a better user experience on mobile devices."

Users can point their mobile browsers to Google's search site, type in the query, then select Mobile Web (beta) as the search option.

Google already offers Google Local, Image Search and Web Search, and Google SMS, a text messaging based service as mobile services.

Nishar didn't discount the possibility of including ads in Mobile Web Search results. "We haven't started doing that," he said, "and Google does not make forward-looking statements." But he said that mobile ads could be delivered as an extension of the company's existing technology.